In papermaking an aqueous solution containing cellulose fibers water/pulp matrix is lain on a wire screen which intraps cellulose fibers and permits a filtrate to be removed. The efficiency of the papermaking is influenced by the retention of the process. Thus measuring of the concentrations in the filtrate reports the action in the papermaking pass. Stated otherwise, the concentration of chemicals in the filtrate reflects what is retained on the wire screen. Chemicals as used herein refers to chemical elements, compounds and compositions.
It is known that the overall retention on the wire screen is directly related to the efficiency of the paper making process. For that reason monitoring of the filtrate is an effective means for establishing the nature of the activity in the papermaking procedure. However, available procedures for investigating the filtrates do not provide adequate information about the chemical constituents in the filler of the filtrate from the aqueous slurry. The filtrate contains a low concentration of fine particle material with chemical constituents in a very low concentration.
Present methods are incapable of readily measuring the low concentrations of the individual chemicals in the filtrate by light reflection. Previous methods have not been able to differentiate between very low concentrations of chemicals and the paper fines in a filtrate of a papermaking slurry.